Recognizing the benefits of exercise contrasted with the various constraints of time and space limiting exercisers in using their lower and upper body muscles, various walking/jogging machines have been designed to provide for physical development and aerobic exercise. It is generally desirable to create a machine that will allow a user to walk or jog without the impact on the user's joints that occur while running on the ground or on a treadmill. There are a number of elliptical machines on the market today which achieve this result, but force the users into an unnatural motion.
In the inventor's previous U.S. Pat. No. 6,758,790, issued Jul. 6, 2004, a walking/jogging exercise machine includes a frame supported upon a generally horizontally extending floor, and a main driveshaft mounted for rotation on the frame. A pair of cams is mounted for rotation on the driveshaft, and a pair of first track assemblies are affixed to the frame. A pair of second track assemblies is rotatably attached to the frame and includes brackets having first rollers which ride upon the peripheries of the cams. A pair of non-aligned, foot assemblies are mounted for sliding movement on the first and second track assemblies. A linkage arrangement is provided between the driveshaft and the foot assemblies for transferring the movement of the foot assemblies to the cams so as to produce a change in the angle of a user's ankle which will result in a natural walking/jogging motion.
While the exercise machine disclosed in the '790 patent has performed generally satisfactorily, it is felt that the walking/jogging machine can be restructured to provide a more enhanced stepping and striding motion. In particular, it is desirable to improve upon the increase in bending of a user's knees concurrent with the change in the user's heel-to-toe movement.